Crane boom constructions



July 12, 1966 M. HAGANES 3,260,374

CRANE BOOM CONSTRUCTIONS Filed June 29, 1964 United States Patent Ofiice 3,268,374 Patented July 12, 1965 3,260,374 CRANE BOOM CONSTRUCTIONS Martin Haganes, Caixa Postal 6498, Sao Paulo, Brazil Filed June 29, 1964, Ser. No. 378,856 3 Claims. (Cl. 21235) The present invention relates to improvements in crane boom constructions and particularly to crane booms adapted to be pivotally mounted on the top of a crane column or stem for movement both in the vertical and horizontal plane, and of the kind having an outer extension crane arm articulated to the outer end of the main body of the crane boom for movement in the vertical plane.

Usually the outer extension crane arm is moved in the vertical plane relative tothe main crane boom by means of a hydraulic pressure cylinder, the inner end of said. cylinder being secured in bearing brackets, rigidly fastened on the main body of the boom, the outer end of the piston rod being articulated to the outer extension crane arm.

This exterior hydraulic cylinder is liable to be damaged by external blows and shocks. It may also easily be overcharged. The provision of a sufliciently lar-ge hydraulic cylinder for cranes used for charging and discharging heavy goods is very expensive.

An object of the present invention is to provide a simple and solid crane boom construction, in which no exterior hydraulic cylinder is needed.

According to the invention the hydraulic cylinder for moving the outer extension crane arm in the vertical plane relative to the crane boom main body is formed by the outer part of the crane boom main body, which is hollow and provided with a piston and a piston rod which is articulated to the piston and the outer extension crane arm. The hydraulic cylinder formed by the outer part of the crane boom main body may be single or double-acting. In the first-mentioned instance it is suflicient to provide just one inlet for hydraulic pressure medium inside the inner position of the piston, and in the second instance a further inlet outside the outer position of the piston must be provided. The outer crane arm extension points downwards and inwards (towards the crane column) in the collapsed position of the crane boom construction, in which collapsed position the piston arranged inside the hollow outer part of the crane boom main body is in its inner position. When the piston is pushed outwards, the outer crane arm will be moved outwards and upwards to the extended position of the crane boom construction.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing, showing a longitudinal side view of the crane boom construction, partly in section, shown in its collapsed position.

Referring to the drawing 1 indicates the vertical crane column or stem mounted on a motor vehicle truck, e.g. a lorry. The crane boom main body 3 is pivotally mounted (3') on the crane column top 2 forming bearing brackets, cooperating with bearing brackets 5, rigidly fastened on the upper inner end of the crane boom main body 3.

The crane boom main body 3 is hollow and forms two aligned cylinders, an inner cylinder 9 and an outer cylinder 13, separated by a transverse partition wall 12. The outer cylinder is formed by the hollow outer part of the crane boom main body 3 and is of particular interest in the present invention.

The inner cylinder 9 has a piston 6 with an inwardly pointing, cylindrical, hollow guide member having an outer bottom, on which a bearing bracket 7 is mounted. An articulated piston rod 8 is connected with the piston 6 and the top 2 of the crane column 1, the one end of the rod 8 being articulated (4) to the top 2 of the column 1, and the other end to the bearing bracket 7. Said inner part of the hollow crane boom main body 3 forms thus a single-acting hydraulic pressure cylinder 9, the inlet a for hydraulic medium (oil) being arranged outside the outer position of the piston 6. This inner cylinder serves to move the whole crane boom construction in the vertical plane relative to the vertical crane column 1.

The outer cylinder 13 formed by the hollow outer part of the crane boom 3 has a piston 15, whose piston rod consists of two articulated rods 16, 10 pivotally connected with each other, the inner end of the inner rod 16 being connected with the piston 15, and the outer end of the outer rod 10 being connected wit-h the outer extension crane arm 11, pivotally mounted (14) on the outer end of the crane boom main body 3 for movement in the vertical plane relative to the main boom 3. The hydraulic pressure medium inlet 12 for the outer cylinder 13 is placed inside the inner position of the piston 15. In the shown embodiment the outer hydraulic cylinder 13 is single-acting. However, a transverse partition wall 17 is provided, and a second medium inlet ("c; dotted lines) may be arranged adjacent the inner side of this wall 17 (outside the outer position of the piston 15) in order to make the cylinder 13 double-acting. In case only a single-acting outer cylinder 13 is required, the wall and the second inlet 0 may be omitted and the articulated rods 16, 10 substituted by a single articulated piston rod.

The crane boom construction operates as follows:

The crane boom construction is shown in its collapsed position in the drawing. When the piston 15 is pushed outwards, the extension crane arm 11 is moved outwards and upwards in the vertical plane to its extended position (not illustrated). When a single-acting outer cylinder 13 is used, the weight of the outer crane arm 11 will cause the pressure medium (oil) to return to the tank once the hydraulic motor is put out of circuit. If a double-acting cylinder 13 is used, the outer crane arm 11 is moved to its collapsed position by pushing the piston 15 inwards.

The inner cylinder 9 formed by the hollow inner part of the crane boom main body 3 forms no real part of the present invention. It is merely shown to illustrate that the main idea of the invention may be utilized for moving the crane boom construction 3, 11 in the vertical plane relative to the crane column 1. By pushing the piston 6 inwards from the shown position, the crane boom 3, 11 will be forced upwards.

What is claimed is:

1. In a crane boom comprising a main body adapted to be pivotally mounted on the top of a crane column for vertical and horizontal movement, an outer arm articulated to the outer end of said main body for vertical movement relative to said main body, a first hollow cylinder defined in the inner part of said main body, a first piston mounted for axial movement in said first cylinder, at first piston rod connected at one of its ends to said first piston and adapted to be operatively connected at the other of its ends to said crane column, fluid-tight partition means disposed in said main body forwardly of the most forward point of travel of said piston, and first hydraulic fluid inlet means communicating with the inside of said first cylinder at a point between said fluid-tight partition means and said most forward point of travel of said first piston, the improvement comprising a second hollow cylinder, said second hollow cylinder being defined in the outer part of said main body, a second piston, said second piston being mounted for axial movement in said second cylinder, said fluid-tight partition means fluidtightly separating said second hollow cylinder from said first hollow cylinder and being disposed rearwardly of the most rearward point of travel of said second piston, a second piston rod connected at one of its ends to said second piston and connected at the other of its ends to said arm, and second hydraulic fluid inlet means communicating with the inside of said second cylinder at a point between said fluid-tight partition means and said most rearward point of travel of said second piston.

2. An improvement in a crane boom as defined in claim 1, further comprising second fluid-tight partition means disposed forwardly of the most forward point of travel of said second piston, said second fluid-tight partition means having a hole defined through it axially of said second cylinder, said second piston rod slidingly and fluid-tightly passing through said hole, and third hydraulic fluid inlet means, said third hydraulic fluid inlet means communicating with the inside of said second cylinder at a point between said second fluid-tight partition means and said most forward point of travel of said second piston.

3. An improvement in a crane boom as defined in claim 2, wherein said second piston rod consists of two rods 5 pivotally connected together.

References Cited by the Examiner UNITED STATES PATENTS 3,035,711 5/1962 Rehnstrom 212-35 FOREIGN PATENTS 1,318,896 1/1963 France.

102,033 6/1963 Norway.

15 EVON C. BLUNK, Primary Examiner.

SAMUEL F. COLEMAN, Examiner.

A. LEVINE, Assistant Examiner. 

1. IN A CRANE BOOM COMPRISING A MAIN BODY ADAPTED TO BE PIVOTALLY MOUNTED ON THE TOP OF A CRANE COLUMN FOR VERTICAL AND HORIZONTAL MOVEMENT, AN ANOTHER ARM ARTICULATED TO THE OUTER END OF SAID MAIN BODY FOR VERTICAL MOVEMENT RELATIVE TO SAID MAIN BODY, A FIRST HOLLOW CYLINDER DEFINED IN THE INNER PART OF SAID MAIN BODY, A FIRST PISTON MOUNTED FOR AXIAL MOVEMENT IN SAID FIRST CYLINDER, A FIRST PISTON ROD CONNECTED AT ONE OF ITS ENDS TO SAID FIST PISTON AND ADAPTED TO BE OPERATIVELY CONNECTED AT THE OTHER OF ITS ENDS TO SAID CRANE COLUMN, FLUID-TIGHT PARTITION MEANS DISPOSED IN SAID MAIN BODY FORWARDLY OF THE MOST FORWARD POINT OF TRAVEL OF SAID PISTON, SAID FIRST HYDRAULIC FLUIT INLET MEANS COMMUNICATING WITH THE INSIDE OF SAID FIRST CYLINDER AT A POINT BETWEEN SAID FLUID-TIGHT PARTITION MEANS AND SAID MOST FORWARD POINT OF TRAVEL OF SAID FIRST PISTON, THE IMPROVEMENT COMPRISING A SECOND HOLLOW CYLINDER, SAID SECOND HOLLOW CYLINDER BEING DEFINED IN THE OUTER PART OF SAID MAIN BODY, A SECOND PISTON, SAID SECOND PISTON BEING MOUNTED FOR AXIAL MOVEMENT IN SAID SECOND CYLINDER, SAID FLUID-TIGHT PARTITION MEANS FLUID TIGHTLY SEPARATING SAID SECOND HOLLOW CYLINDER FROM SAID FIRST HOLLOW CYLINDER AND BEING DISPOSED REARWARDLY OF THE MOST REARWARD POINT OF TRAVEL OF SAID SECOND PISTON, A SECOND PISTON ROD CONNECTED AT ONE OF ITS ENDS TO SAID SECOND PISTON CONNECTED AT THE OTHER OF ITS ENDS TO SAID ARM, AND SECOND HYDRAULIC FLUID INLET MEANS COMMUNICATING WITH THE INSIDE OF SAID SECOND CYLINDE AT A POINT BETWEEN SAID FLUID-TIGHT PARTITION MEANS AND SAID MOST REARWARD POINT OF TRAVEL OF SAID SECOND PISTON. 